A campaign of letters for cleaner air addressed to the chief executive by a group of primary school pupils has gathered momentum, with more schools joining in. But Donald Tsang Yam-kuen will not be in Hong Kong to accept their letters. Following the example of Beacon Hill School in Kowloon Tong, students from all sections of the English Schools Foundation (ESF) and other public and private schools will add their letters to the increasing clamour for action on air pollution. The plan is for student representatives to deliver the letters to Government House on World Environment Day, June 5. An organiser said they would apply for a police permit for the occasion because the number of student petitioners was expected to exceed 30. 'I've had so many people ringing and e-mailing, and they are seriously glad that something is taking place and want to join in. Children and teachers are talking about this as an important symbolic gesture,' said Heather Quinn, an organiser and a teacher at Beacon Hill School. The school has also collected signatures from parents and has raised about $70,000 for a garden on the school premises. A spokeswoman for Mr Tsang's office said: 'The chief executive has read many of the letters written by the students. He is impressed by how much they care for our environment.' She said the government would carefully consider their views and suggestions. The Environmental Protection Department had replied to the students on May 9, explaining the government's efforts to improve air quality. The office said staff at Government House would receive any letters delivered in person and addressed to the chief executive, but noted that Mr Tsang would be away from Hong Kong for a Pearl River Delta co-operation forum on the day the students planned to deliver their petitions. Meanwhile, students at West Island School in Pokfulam on Thursday put pen to paper to join the campaign during their own anti-pollution day.